Determining window efficiency setting for use in humidity control of a building

ABSTRACT

A controller for operating HVAC equipment of a building having one or more windows. The HVAC equipment includes a heater and a humidifier. The controller receives an indoor temperature and an outdoor temperature, determines a thermal efficiency of the building based on the indoor temperature, the outdoor temperature and control signals provided to the heater indicative of a thermal demand on the heater, determines a window efficiency setting based on the thermal efficiency, determines a humidity threshold based on the window efficiency setting and the outdoor temperature, and controls the humidifier of the building to not raise the humidity in the building above the humidity threshold.

TECHNICAL FIELD

The disclosure relates generally to operating heating, ventilation and/or air conditioning (HVAC) equipment, and more particularly to controllers for HVAC equipment.

BACKGROUND

The HVAC system of many buildings include both a heater and a humidifier. In colder climates, and during the heating season, the outside air can become very dry. The low temperature of outside air can dramatically reduce the total amount of water vapor the air can hold. Either intentionally through outside air ventilation or because of inherent leaks in the building structure, the interior air of the building is constantly replaced by this dry outside air. This causes the humidity level within the building to fall to uncomfortably low levels. For example, air at −20° F. and 100% Relative Humidity (RH) when heated to 70° F. has a RH of less than 10%, which is uncomfortably low. This is why people's skin tends to dry out so much when it's cold outside. Low humidity can also have detrimental effects on the building itself. For example, hardwood floors, wood trim and other materials can become very dry and crack.

To combat this, a humidify is often provided as part of the HVAC system. The humidifier adds water vapor to the inside air to bring the RH up to a more comfortable level. However, if too much water vapor is added to the inside air, condensation can occur on cold surfaces such as on the inside surfaces of the windows. Window surfaces are typically the coldest interior surfaces in the heated space, since they are typically the most poorly insulated. When the interior surface temperature of a window falls to a temperature that is below the dew point temperature in the space, then condensation on the interior window surface occurs. If the difference between interior window surface temperature and the dew point temperature becomes too high, so much condensation can occur that moisture runs onto the window frames, which can cause damage over time. As such, it is desirable to limit the interior humidity level to a value such that the dew point is below the window surface temperature. It is desirable have the dew point temperature near (but below) the window temperature in order to provide increased comfort to the occupants of the interior space.

The changing outdoor temperature changes the window surface temperature and hence the maximum amount of water vapor acceptable in the interior space. The changing outdoor temperature also changes the amount of water vapor in the outdoor air, which replaces the indoor air through ventilation or the like. Temperature setbacks programmed into a thermostat for energy-saving purposes will affect the indoor air temperature, which also affects the window surface temperature. All of these present challenges to controlling condensation on the window surface.

Moreover, different windows can have different thermal window efficiencies. For example, a given outdoor temperature change will often result in a larger temperature change on the inside surface of a single pane window than on a double or triple pane window. Also, the size a window can affect the window efficiency. In some prior art systems, a user was allowed to select a window efficiency setting (e.g. on a scale of 1 to 5) via a user interface of a thermostat or the like. The thermostat would use the user selected window efficiency setting to automatically adjust the maximum allowed humidity level based on the current outdoor temperature. The thermostat would then control the humidifier accordingly. In such systems, the user typically initially guessed at their window efficiency setting and waited to see if water condensed on the windows. If so, the user would adjust the window efficiency setting down. The user would typically repeat this over several days until water condensation no longer occurred. While this approach is workable, it is a relatively inefficient and error prone way of arriving at a window efficiency setting. What would be desirable is an approach for automatically determine a window efficiency setting for a building, and then controlling the indoor humidity accordingly.

SUMMARY

This disclosure relates generally to operating heating, ventilation and/or air conditioning (HVAC) equipment, and more particularly to automatically determining a window efficiency setting for a building and controlling the humidify in the building based on the determined window efficiency setting. This may be accomplished by determining a measure of thermal efficiency of the building by, for example, monitoring the indoor temperature, the outdoor temperature and either or both of a thermal demand on the heater and/or a change in the inside temperature of the building during a period when the heater remains off. The determined thermal efficiency of the building may be used to determine a window efficiency setting for the building. The window efficiency setting may then be used to automatically adjust a maximum allowed humidity level in the building based on the current outdoor temperature. The humidifier may be controlled accordingly. In some cases, the window efficiency setting may be determined without any input from user. In other cases, the user may provide some basic additional information regarding the windows and/or the building, such as the number of window panes in the windows, the manufacturer of the windows, the model of the windows, the R-value for the windows, the year of construction of the building, the R value for the building walls, the R value of the building ceiling, the total number of windows in the building, the size of the largest window in the building, the size of the window in what is expected to be the coldest location in the building, and/or other information.

In one example, a controller for operating heating, ventilation and/or air conditioning (HVAC) equipment that may include a heater and a humidifier of a building having one or more windows. The controller may be configured to receive an indoor temperature within the building and an outdoor temperature outside of the building, determine a measure of thermal efficiency of the building based at least in part on the indoor temperature, the outdoor temperature and one or more control signals provided to the heater that are indicative of a thermal demand on the heater, determine a window efficiency setting based at least in part on the determined measure of thermal efficiency, determine a humidity threshold based at least in part on the window efficiency setting and the outdoor temperature, and control the humidifier of the building to not raise the humidity in the building above the humidity threshold.

Alternatively or additionally to the foregoing, the measure of thermal efficiency of the building may be determined while the heater is controlling the indoor temperature of the building in accordance with a constant temperature setpoint.

Alternatively or additionally to any of the embodiments above, the heater may comprise a modulating furnace with a modulating heat output that is modulated by a control input, and wherein the one or more control signals include the control input.

Alternatively or additionally to any of the embodiments above, the control input to the modulating furnace may be provided by a PI controller.

Alternatively or additionally to any of the embodiments above, the heater may be cycled on and off by a heater relay output to control the indoor temperature of the building in accordance with a temperature setpoint, wherein the one or more control signals may include the heater relay output.

Alternatively or additionally to any of the embodiments above, a cycle rate of the heater relay output may be indicative of the thermal demand on the heater.

Alternatively or additionally to any of the embodiments above, the controller may comprise a thermostat located within the building.

Alternatively or additionally to any of the embodiments above, at least part of the controller may be implemented in a server remote from the building.

In another example, a controller for operating HVAC equipment of a building having one or more windows. The controller may be configured to receive an indoor temperature within the building and an outdoor temperature outside of the building, cycle a heater ON and OFF to control the indoor temperature of at least part of the building in accordance with a temperature schedule, wherein the temperature schedule includes a plurality of time periods each with a corresponding temperature setpoint, and wherein the temperature schedule includes a comfort time period with a comfort temperature setpoint followed by a setback time period immediately following the comfort time period with a lower setback temperature setpoint. The controller may be further configured to determine a measure of thermal efficiency of the building based at least in part on the indoor temperature, the outdoor temperature and a rate of change of the indoor temperature during a sensing period extending from after the heater is cycled OFF at the end of the comfort time period to before the indoor temperature reaches the lower setback temperature setpoint of the immediately following setback time period, determine a window efficiency setting based at least in part on the determined measure of thermal efficiency, determine a humidity threshold based at least in part on the window efficiency setting and the outdoor temperature, and control a humidifier of the building to not raise the humidity in the building above the humidity threshold.

Alternatively or additionally to any of the embodiments above, the controller may be configured to determine a measure of thermal efficiency of the building based at least in part on the indoor temperature, the outdoor temperature and the rate of change of the indoor temperature during a period after a user manually adjusts a current temperature setpoint downward to a lower temperature setpoint to before the indoor temperature reaches the lower temperature setpoint.

Alternatively or additionally to any of the embodiments above, the heater may remain OFF during the sensing period.

Alternatively or additionally to any of the embodiments above, the controller may comprise a thermostat located within the building.

Alternatively or additionally to any of the embodiments above, at least part of the controller may be implemented in a server remote from the building.

In another example, a controller for operating HVAC equipment of a building having one or more windows, the HVAC equipment including a heater and a humidifier, may be configured to receive an indoor temperature within the building and an outdoor temperature outside of the building, determine a measure of thermal efficiency of the building based at least in part on the indoor temperature, the outdoor temperature and a sensed parameter that is related to a rate of heat loss of the building, receive information from a user regarding the one or more windows, determine a window efficiency setting based at least in part on the determined measure of thermal efficiency and the information received from the user regarding the one or more windows, determining a humidity threshold based at least in part on the window efficiency setting and the outdoor temperature, and controlling a humidifier of the building to not raise the humidity in the building above the humidity threshold.

Alternatively or additionally to any of the embodiments above, the information received from the user may include one or more of a total number of windows in the building, a number of window panes in the windows in the building, a manufacturer of the windows in the building, a type of the windows in the building, a model number of the windows in the building, and an age of the windows of the building.

Alternatively or additionally to any of the embodiments above, the controller may further receive information from the user regarding the building, and determine the window efficiency setting based at least in part on the determined measure of thermal efficiency, the information received from the user regarding the one or more windows and the information received from the user regarding the building.

Alternatively or additionally to any of the embodiments above, the information received from the user regarding the building may include one or more of a building square feet, a R-value of walls of the building, a wall thickness of the building, and an age of the building.

Alternatively or additionally to any of the embodiments above, the controller may further receive information from a public database regarding the building, and determine the window efficiency setting based at least in part on the determined measure of thermal efficiency, the information received from the user regarding the one or more windows and the information received from the public database regarding the building.

Alternatively or additionally to any of the embodiments above, the controller may comprise a thermostat located within the building.

Alternatively or additionally to any of the embodiments above, at least part of the controller may be implemented in a server remote from the building.

The above summary of some illustrative embodiments is not intended to describe each disclosed embodiment or every implementation of the present disclosure. The Figures and Description which follow more particularly exemplify these and other illustrative embodiments.

BRIEF DESCRIPTION OF THE FIGURES

The disclosure may be more completely understood in consideration of the following description in connection with the accompanying drawings, in which:

FIG. 1 is a schematic block diagram of an illustrative building automation system;

FIG. 2 is a schematic floorplan view of a building, house, or other structure;

FIG. 3 is a schematic block diagram of another illustrative building automation system; and

FIG. 4 is a flow diagram of an illustrative method.

While the disclosure is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the disclosure to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure.

DESCRIPTION

For the following defined terms, these definitions shall be applied, unless a different definition is given in the claims or elsewhere in this specification.

All numeric values are herein assumed to be modified by the term “about,” whether or not explicitly indicated. The term “about” generally refers to a range of numbers that one of skill in the art would consider equivalent to the recited value (i.e., having the same function or result). In many instances, the terms “about” may include numbers that are rounded to the nearest significant figure.

The recitation of numerical ranges by endpoints includes all numbers within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.

It is noted that references in the specification to “an embodiment”, “some embodiments”, “other embodiments”, etc., indicate that the embodiment described may include one or more particular features, structures, and/or characteristics. However, such recitations do not necessarily mean that all embodiments include the particular features, structures, and/or characteristics. Additionally, when particular features, structures, and/or characteristics are described in connection with one embodiment, it should be understood that such features, structures, and/or characteristics may also be used connection with other embodiments whether or not explicitly described unless clearly stated to the contrary.

The following description should be read with reference to the drawings in which similar structures in different drawings are numbered the same. The drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the disclosure.

Controllers may be adapted to control Heating, Ventilation, and/or Air Conditioning (HVAC) equipment. In some cases, the HVAC equipment may be located within or around a structure that has one or more windows, such as a house or building. In some cases, the controller may be a thermostat. HVAC equipment can include heaters or furnaces, ventilators, air conditioning systems, fans, heat pumps, humidification/dehumidification systems, etc. In some cases, the controller may be connected to the HVAC equipment using a wired or wireless connection, or a combination thereof to communicate and control the HVAC equipment. Certain controllers of the present disclosure may be found in an HVAC system, a method, and/or a non-transitory computer-readable storage medium with an executable program stored thereon for operating HVAC equipment of a building having one or more windows.

In some cases, the controller(s) may be configured to receive an indoor temperature within the building and an outdoor temperature outside of the building. The controller(s) may determine a measure of the thermal efficiency of the building based on the indoor temperature, the outdoor temperature, and control signals provided to a heater of the HVAC equipment that may be indicative of a thermal demand on the heater. The controller(s) may determine a window efficiency setting based on the measured thermal efficiency and determine a humidity threshold based on the window efficiency setting and the outdoor temperature. The controller(s) may then control a humidifier of the HVAC equipment to not raise the humidity in the building above the humidity threshold.

FIG. 1 is a schematic block diagram of an illustrative building automation system. The illustrative building automation system includes a controller 100 that may provide control signals to HVAC equipment 124. The HVAC equipment 124 may include a heater, such as a gas or electric furnace, and a humidifier. In some cases, the HVAC equipment 124 may include additional HVAC equipment such as a ventilator, dehumidifier, an air conditioner, and/or any other suitable HVAC equipment.

In some cases, the controller 100 may be a thermostat located within a building, but this is not required. The illustrative controller 100 includes a processor 112 (e.g., microcontroller, microprocessor, etc.) operatively coupled to a memory 102, a user interface 114, a transmitter 108 (sometimes a transceiver), a temperature sensor 110, a humidity sensor 118, and an I/O port 116. The temperature sensor(s) (e.g., temperature sensor 110), humidity sensor(s) (e.g., humidity sensor 118), and/or the memory 102 may be located in a housing of the controller 100 and/or located remotely from the controller 100.

In some cases, the controller 100 may communicate with one or more devices such as the HVAC equipment 124. In some examples, the transmitter 108 may be used to communicate commands from the controller 100 to a heater of the HVAC equipment 124 to cycle the heater ON and OFF to control an indoor temperature of the building in accordance with one or more temperature set points. In some instances, the one or more temperature set points may be included in temperature schedule stored in the memory 102 and implemented by the controller 100, but this is not required.

In some cases, the transmitter 108 may be connected to the HVAC equipment 124 a wired and/or wireless connection, and in some cases may communicate with the HVAC equipment 124 using one or more communication protocols. For example, in some examples, the transmitter 108 may communicate with the HVAC equipment 124 through serial and/or parallel communication using a building automation protocol, such as BACnet. This is just one example of a building control network protocol that may be used to facilitate communication between the controller 100 and the HVAC equipment 124. Other building control network protocols are also contemplated include, but not limited to, Redlink, 1-Wire, C-Bus, CC-Link Industrial Networks, DSI, Dynet, KNX, LonTalk, oBIX, VSCP, xAP, X10, Z-Wave, ZigBee, INSTEON, TCIP, and/or Ethernet.

In some cases, the transmitter 108 may be connected to the HVAC equipment 124 via a wired connection (e.g. one or more field wires) and/or via a wireless connection. For example, the transmitter 108 may assert predetermined control signals onto field wires by activating a relay or other switch (e.g. FET) to control the HVAC equipment 124. In another example, the transmitter 108 may provide control signals to the HVAC equipment 124 via a wireless network such as WiFi, Redlink, Zigbee or the like.

In some instances, the processor 112 of the controller 100 may include a pre-programmed chip, such as a very-large-scale integration (VLSI) chip and/or an application specific integrated circuit (ASIC). In such embodiments, the chip may be pre-programmed with control logic in order to control the operation of the controller 100. In some cases, the pre-programmed chip may implement a state machine that performs the desired functions. By using a pre-programmed chip, the processor 112 may use less power than other programmable circuits (e.g. general purpose programmable microprocessors) while still being able to maintain basic functionality. In other instances, the processor 112 may include a programmable microprocessor. Such a programmable microprocessor may allow a user to modify the control logic of the controller 100 even after it is installed in the field (e.g. firmware update), which may allow for greater flexibility of the controller 100 in the field over using a pre-programmed ASIC. In either case, the processor 112 may be programmed to direct the controller 100 to control the HVAC equipment 124.

In some cases, the memory 102 may be operatively coupled to the processor 112 and may be used to store any desired information, such as the aforementioned temperature schedule including a plurality of time periods each having a corresponding temperature setpoint. For instance, the temperature schedule may include a constant temperature setpoint, a comfort time period with a comfort temperature setpoint, and/or a setback time period with a setback temperature setpoint. The memory 102 may be any suitable type of storage device including, but not limited to, RAM, ROM, EPROM, flash memory (e.g., NAND flash memory), an external SPI flash memory, a hard drive, and/or the like. In some cases, the memory 102 may include two or more types of memory. For example, the memory 102 may include a RAM, a ROM and a flash memory module. During operation, the processor 112 may store information within the memory 102, and may subsequently retrieve the stored information from the memory 102. In some cases, the memory 102 may store the instructions (e.g. software) executed by the processor 112.

In some cases, the controller 100 may include and/or may communicate with a plurality of environmental sensors. For instance, as shown in FIG. 1, the controller 100 may include a temperature sensor 110 and a humidity sensor 118. In some examples, the temperature sensor 110 may be used to identify an indoor temperature. In some cases, another temperature sensor 111 may be provided to identify an outdoor temperature outside of the building. In some cases, the humidity sensor 118 may be used to identify an indoor humidity inside of the building. In some cases, another humidity sensor 119 may be provided to identify an outdoor humidity outside of the building. In some instances, the controller 100 may include more or less environmental sensors. In some cases, an outside temperature and/or an outside humidity may be reported to the controller 100 from a remote device 122 via a network 120. The remote device 122 may provide current local weather data to the controller 100, such as the current outdoor temperature, current outdoor humidity, etc.

In some cases, the processor 112 may monitor control signals that are provided to the heater, such as heater relay output used to cycle the heater(s) ON and OFF or control inputs for modulating a heat output of the modulating heater(s), for example. In some cases, the control signals may be used to estimate a current thermal demand on the heater while maintaining a fixed set point, and thus may represent the thermal loss of the building at that particular indoor/outdoor temperature combination.

The processor 112 may use the transmitter 108 to communicate control signals for cycling a heater(s) of the HVAC equipment 124 ON and OFF or modulating an output of a modulating heater to control the indoor temperature of the building in accordance with one or more temperature setpoints and/or temperature schedules. In some cases, the processor 112 may determine a thermal demand on the HVAC equipment 124 from the cycle ON time and the cycle OFF time. For example, the thermal demand on the HVAC equipment 124 may be proportional or otherwise related to the cycle rate of the HVAC equipment 124 (e.g. the period of one ON/OFF cycle). In other cases, the processor 112 may determine a thermal demand on the HVAC equipment 124 from a modulated output that is provided to a modulating heater. For example, the thermal demand on the HVAC equipment 124 may be proportional or otherwise related to the modulated output (e.g. 45% of Max) provided to the HVAC equipment 124. These are just examples.

In some cases, a temperature schedule may include a plurality of time periods, such as a comfort time period and a setback time period, each with a corresponding temperature setpoint. In some instances, the setback time period may be immediately after the comfort time period. In some cases, the processor 112 may receive the indoor temperature within the building and the outdoor temperature outside of the building from the temperature sensors 110 and 111. The processor 112 may determine a rate of change of the indoor temperature during a sensing period that begins after the heater is cycled OFF but before the heater is cycled back ON again (e.g. during a period when the heater remains OFF). In one example, the sensing period may begin at the end of the comfort time period and extend to before the indoor temperature reaches the lower setback temperature setpoint of the setback time period. In another example, the user the heater may be simply turned off for a sensing period of time, and over-ride a current temperature schedule if any. In any event, this may provide a rate of thermal loss from the building when no heat is being added to the building by the heater. The processor 112 may use the received indoor temperature, the outdoor temperature, and the rate of change of the indoor temperature to determine a measure of thermal efficiency of the building.

Regardless of how the measure of thermal efficiency of the building is determined, it is contemplated that the processor 112 may use the measure of thermal efficiency of the building to determine a window efficiency setting, and then use the window efficiency setting and the received outdoor temperature to determine a humidity threshold for the building. The humidity threshold will be dependent on the window efficiency setting, the outdoor temperature, and to some degree the indoor temperature. In some cases, the processor 112 may use the transmitter 108 to communicate instructions for controlling the humidifier so as to not raise the humidity in the building above the humidity threshold.

A user interface 114 may be provided for the controller 100. The user interface 114 may be operatively coupled to the processor 112, and may permit a user to view and manage the operation the HVAC equipment 124 that service the building, house, or other structure. In some cases, the user may be able to group one or more device from the HVAC equipment 124 to form an operating group to establish operating zones or areas within the building, house, or other structure. Alternatively, or in addition, the user may be able to set or modify programmable setpoints and/or set or modify a temperature schedule for HVAC equipment and/or a group of HVAC equipment to control the environmental conditions of specifics areas within the building. Different programmable setpoints and/or temperature schedules may be selected for different HVAC equipment and/or groups of HVAC equipment, if desired. When provided, the ability to view and manage multiple HVAC equipment servicing different areas of a building may facilitate improved management of the building.

In some cases, the user interface 114 may be a physical user interface that is accessible at the controller 100 and may include a display 104 and/or a distinct keypad 106. The display 104 may be any suitable display. In some instances, the display 104 may include or may be a liquid crystal display (LCD), an OLED, etc., and in some cases a fixed segment display, a dot matrix LCD display, a 7-segment type display, and/or may include one or more LEDs. In some cases, the display 104 may include a touch screen LCD panel that functions as both the display 104 and keypad 106. The user interface 114 may be adapted to solicit values for a number of operating parameters, programmable setpoints, and/or to receive such values, but this is not required.

In some cases, the user interface 114 may receive information from a user regarding one or more windows of the building and/or user information regarding the building, although this is not required. For example, the information regarding the windows may include, but is not limited to, the total number of windows in the building 200, the number of window panes in the windows, the manufacturer of the windows, the type of the windows, the model number of the windows, the R-value for the windows, a size of the largest window in the building, a size of the window in what is expected to be the coldest location in the building, and/or the age of the windows. In some cases, the information regarding the building may include, but is not limited to, the age of the building, the square footage of the building 200, the R-value of the walls of the building, the wall thickness of the building, and the age of the building. In some cases, the controller 100 may use information regarding the building 200, received from a public database, to determine the window efficiency setting. For example, the information from the public database may include, but is not limited to, the age of the building, the repairs performed to the building 200, the year and make/model of the HVAC equipment in or around the building, and the current and past occupants of the building. These are just a few examples of factors regarding the building 200 that may be used to determine the window efficiency setting. In some cases, more or alternative factors may be used to obtain a more accurate measure of the window efficiency setting.

In some cases, the user interface 114 may be provided as a separate unit from the controller 100, and may facilitate a user's interactions with the controller 100 located within the building, house, or other structure. For example, the user interface 114 may be provided as part of a remote device (e.g., remote device 122), such as a smart phone, a tablet computer, a laptop computer, or a desktop computer. In some cases, the user interface 114 may communicate with the controller 100 via a network such as, for example, a network 120 (e.g. Internet, Wifi, etc.).

In some instances, the I/O port 116 of the controller 100 may permit the controller 100 to communicate over one or more additional wired or wireless networks (e.g., the network 120) that may accommodate remote access and/or control of the controller 100 via a remote device 122 such as, for example, a smart phone, tablet computer, laptop computer, personal computer, PDA, server, and/or the like. In some cases, the remote device 122 may provide a primary and/or a secondary user interface for the user to interact with the controller 100. In some cases, the controller 100 may utilize a wireless protocol to communicate with the remote device 122 over the network 120. In some cases, the network 120 may be a may be a Local Area Network (LAN) such as a Wi-Fi network or a Wide Area Network (WAN) such as the Internet. These are just some examples.

In some cases, the remote device 122 may execute an application program that facilitates communication and control of the controller 100. The application program may be provided by and downloaded from an external web service (e.g. Apple Inc.'s ITUNES®, Google Inc.'s Google Play, a proprietary server, etc.) for this purpose, but this is not required. In one example, the application program may cause the remote device 122 to receive and store data, such as temperature setpoints and/or a temperature schedule received from the controller 100. The application program may translate the data received from the controller 100 and display the data to the user via the user interface of the remote device 122. Additionally, the application program may be capable of accepting an input from a user through the user interface of the remote device 122 and transmitting accepted input to the controller 100. For example, if the user inputs include information about a building and/or the windows on the building, comfort temperature setpoint changes, setback temperature setpoint changes, schedule changes, sensing period changes, and/or other changes, the application program may transmit these changes to the remote device 122. In some cases, the remote device 122 may provide current local weather data to the controller 100, such as the current outdoor temperature.

FIG. 2 is a schematic floorplan view of a building, house, or other structure 200 having a number of windows 206A-206L. As shown, in some cases, the controller 100 and the HVAC equipment 124 (e.g. heater 202 and humidifier 204) may be located inside the building 200. In some examples, the controller 100 may be embodied in a thermostat, but this is not required. In some cases, the heater 202 may be used by the controller 100 to control an indoor temperature inside the building 200. In some cases, the humidifier 204 may be used by the controller 100 to control an indoor humidity inside the building 200. It will be generally understood that the HVAC equipment 124 may be expanded and adapted to control and manage other environmental conditions in the building. In addition, the controller 100, as described herein, may provide a wireless retrofit solution for buildings employing older HVAC equipment that may be wired and that are currently incapable of receiving a wireless or digital command signal. For example, the controller 100 may be configured to coordinate operational control of multiple HVAC equipment components servicing the building or structure 200 that otherwise operate independently of one another. This may increase operational efficiency, reduce operational costs and/or maximize energy efficiency of the building or structure 200 in which the controller 100 is deployed.

The heater 202, shown in FIG. 2, may be any type of suitable heater including, for example, a single-stage furnace, a two-stage furnace, a modulating furnace, etc. In some example, the heater 202 may be cycled ON and OFF to thermostatically control the inside temperature of the building 200. When so provided, the controller 100 may provide a heater relay output that cycles the heater 202 ON and OFF in accordance with a temperature setpoint provided by the controller 100. In some instances, a cycle rate of the heater relay output may indicate the thermal demand on the heater 202, and may be used by the controller 100 to determine a measure of thermal efficiency of the building 200.

In another example, the heater 202 may be modulated between, for example, 25% and 100% of a maximum heat output. When so provided, the controller 100 may provide a modulated control signal that modulates the heater 202 between 25% and 100% over time to thermostatically control the inside temperature of the building 200. When so provided, the modulated control signal (e.g. 36%) may indicate the thermal demand on the heater 202, and may be used by the controller 100 to determine a measure of thermal efficiency of the building 200.

In a simplified example, the controller 100 may be used to control the single heater 202 and a single humidifier 204 of the HVAC equipment 124. In other cases, the controller 100 may be used to communicate with and control multiple pieces of equipment belonging to the HVAC equipment 124. The HVAC equipment 124 may be located in different areas, zones, or rooms of the building 200 and may be mounted, for example, on a wall, ceiling, or in a window opening of the building or structure 200.

As shown, in some cases, one or more temperatures sensors 110 may be located inside the building and one or more temperature sensor 111 may be located outside the building 200 such that the temperature sensors 110 and 111 can obtain an accurate reading of the indoor and outdoor temperature, respectively. An indoor humidity sensor 118 may be located inside the building. The controller 100 may receive the indoor temperature, the outdoor temperature and the indoor humidity from the temperature sensors 110 and 111 and the humidity sensor 118. In some cases, the thermal efficiency of the building 200 may be an important factor in controlling the indoor environmental conditions of the building 200. In some cases, the controller 100 may use the indoor temperature, the outdoor temperature, and control signals indicative of the thermal demand on the heater 202 to determine a measure of thermal efficiency of the building 200. In some instances, the measure of the thermal efficiency of the building 200 may be determined while the heater 202 is controlling the indoor temperature of the building in accordance with a constant or fixed temperature setpoint. For example, when the heater 202 is a modulating furnace, the controller 100 may provide a control input (0-100%) that modulates the heat output of the heater 202 so that the indoor temperature inside the building 200 is thermostatically controlled to a constant or fixed temperature setpoint. The control input, along with the outside and/or inside temperature, may be used to determine a measure of the thermal efficiency of the building. Alternatively, when the heater 202 is a non-modulating furnace, the cycle ON/OFF rate, along with the outside and or inside temperature, may provide a measure of the thermal efficiency of the building.

In some cases, the controller 100 may be programmed with a temperature schedule and the controller 100 may communicate instructions to heater 202 for cycling the heater 202 ON and OFF to control the indoor temperature of the building 200 in accordance with the temperature schedule. In some cases, the temperature schedule may include a plurality of time periods, such as a comfort time period and a setback time period, each with a corresponding temperature setpoint. In some instances, the setback time period may be immediately after a comfort time period. During a sense period after a comfort time period and during a time when the heater 202 is OFF and the building is cooling down to the setback temperature, the controller 100 may determine a rate of change of the indoor temperature. This rate of change may be indicative of heat loss from the building. The controller 100 may use the rate of change of the indoor temperature during the sensing period, the outdoor temperature and in some cases the indoor temperature to determine a measure of thermal efficiency of the building.

In some cases, the controller 100 may use the thermal efficiency of the building 200 to determine a window efficiency setting. In some instances, the controller 100 may use the thermal efficiency of the building 200 to determine a rate of energy loss and determine how much of the rate of energy loss is likely attributable to the windows 206A-206L to identify the window efficiency setting. In some cases, additional factors may be used when determining the window efficiency setting. For instances, the controller 100 may use information received from a user regarding the windows 206A-206L and information regarding the building 200 to help determine the window efficiency setting. For example, the information regarding the window may include, but is not limited to, the number of window panes in the windows, the manufacturer of the windows, the model of the windows, the age of the windows, the type of the windows, an R-value for the windows, a total number of windows in the building, a size of the largest window in the building, a size of the window in what is expected to be the coldest location in the building, and/or another information. In some cases, the information regarding the building may include, but is not limited to, the square footage of the building 200, the R-value of the walls of the building, the R-value of the attic of the building, the wall thickness of the building, and the age of the building, the style of the building (rambler, 2-story, split level, etc.). In some cases, the controller 100 may use information regarding the building 200, received from a public database, to determine the window efficiency setting. For example, the information from the public database may include, but is not limited to, the repairs performed to the building 200, the year and make/model of the HVAC equipment in or around the building, the age of the building (and thus applicable building codes), and the current and past occupants of the building. These are just a few examples of factors regarding the building 200 that may be used to help determine the window efficiency setting. In some cases, more or alternative factors may be used to obtain a more accurate measure of the window efficiency setting.

In some cases, the controller 100 may use the window efficiency setting, along with the current outdoor temperature, to determine a humidity threshold for the building 200. The humidity threshold intended to keep the dew point of the air inside of the building below the temperature of the inside surface of the windows. The controller 100 may then control the humidifier 204 of the building 200 to not raise the humidity in the building above the humidity threshold. In some cases, the controller 100 may also control a ventilator (not shown) that draws in outside air and expels inside air, to help reduce the humidity level in the building when it is necessary to do so, such as when transitioning from a comfort temperature setpoint to a setback temperature setpoint or when the outside air temperature drops rapidly. Alternatively, or in addition, the controller 100 may activate a dehumidifier to reduce the humidity level in the building when desired.

FIG. 3 is a schematic block diagram of another illustrative building automation system 300. The illustrative building automation system 300 includes a server 302 operatively coupled to an HVAC controller 301 via a network 324. The HVAC controller 301 is operatively coupled to and configured to provide control signals to the HVAC equipment 124. In some cases, the server 302 may be remote from the building (e.g., building 200, from FIG. 2) where the HVAC equipment 124 is located. In some cases, the server 302 may be in the cloud and may serve a plurality of customers buildings. In some instances, the server 302 may collect data from the HVAC controllers 301 of each of the plurality of customer buildings, and may process the collected data (e.g. big data) to help identify the thermal efficiency and/or the window efficiency setting of a particular one of the customer buildings. For example, the server 302 may identify existing customer buildings that have similar characteristics (e.g. building age, building location, building location, type of windows, number of windows, etc.) to a new customer building, and may use the thermal efficiency and/or the window efficiency setting of the existing customer buildings that have similar characteristics to help identify the thermal efficiency and/or the window efficiency setting of the new customer building. The server 302 may in some cases repeatedly recalculate the thermal efficiency and/or the window efficiency setting for each customer building over time based on new information provided by a corresponding HVAC controller. When so provided, the server 302 may determine when the thermal efficiency and/or the window efficiency setting begins to deviate from an original setting or from the settings of buildings with similar characteristics, and may issue an alarm in response. These are just an examples.

In the example shown in FIG. 3, the HVAC equipment 124 may include a heater 202 and a humidifier 204. In some cases, the HVAC equipment 124 may include other devices such as one or more ventilators, dehumidifiers, Air Handing Units (AHU), Variable-Air-Volume (VAV) units, dampers, valves, fans, heating units, cooling units, sensors, thermostats, humidifiers, dehumidifiers etc., which allow for the monitoring and/or control of temperature and/or other environmental conditions in a building.

In the example shown, the server 302 can perform various communication and data transfer functions and can execute one or more application functions. The components of server 302 may include, but are not limited to, a controller 304, memory 306, a network adapter 308 and a bus 310 that couples various system components including the memory 306 to the controller 304. The controller 304 may execute instructions stored in the memory 306. The controller 304 and the memory 306 may be configured similar to the controller 100 and the memory 102 described with respect to FIG. 1. In some cases, the controller 304 and the memory 306 may have additional functionality and storage capacity as desired to facilitate proper management of the HVAC equipment. In some cases, the server 302 may be operatively connected to the HVAC controller 301 through a wired or wireless network 324. In some examples, the network 324 may be a local area network (LAN), a general wide area network (WAN), and/or a public network (e.g., the Internet). The network 324 may include, for example, copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers. In some instances, the network adapter 308 is included in the server 302 to support communication over the network 324. In some cases, the server 302 and the HVAC controller 301 distribute the control function for the HVAC equipment 124. The particular control functions provided by each of the server 302 and the HVAC controller 301 may be allocated as desired, depend on the goals of the system at hand.

The memory 306 can include computer system readable media in the form of volatile memory, such as random access memory (RAM) 312 and/or cache memory 314. The server 302 may further include other removable/non-removable, volatile/non-volatile computer system storage media. By way of example only, storage system 316 can be provided for reading from and writing to a non-removable, non-volatile magnetic media (not shown and typically called a “hard drive”).

Program/utility 318 may be stored in the memory 306 and may include one or more application program modules (e.g. software), such as a temperature schedule 320. In some cases, the program/utility 318 may include additional program modules as well as an operating system, one or more other application program modules, and program data. According to various embodiments, the application program modules (e.g., the temperature schedule 320) may include time periods and temperature setpoints 322, for example.

The temperature schedule 320 may execute on the server 302. In some cases, the temperature schedule 320 may execute on HVAC controller 301. In some cases, part of the temperature schedule 320 may be executed on the server 302 and part of the temperature schedule 320 may be executed on the HVAC controller 301.

In some cases, the controller 304 of the server 302 may receive indoor temperatures and outdoor temperatures of a building. In some cases, the controller 304 may receive the indoor temperatures and outdoor temperatures from the HVAC controller 301 of a building. In some cases, the controller 304 may receive the indoor temperatures from the HVAC controller 301 of a building, and may receive the outdoor temperature from a weather service accessible via the network 324 for the location (e.g. zip code) of the building. The controller 304 may also receive an indication from the HVAC controller 301 an measure of demand on the heater 202 of the HVAC equipment 124 of the building.

In some cases, the controller 304 may use the indoor temperature, the outdoor temperature, and the measure of demand on the heater 202 to determine a measure of thermal efficiency of the building. The controller 304 may then use the thermal efficiency of the building to determine a window efficiency setting for the building. In some examples, the controller 304 may map the thermal efficiency of the building to a corresponding window efficiency setting for the building (e.g. using look up table or the like). In other cases, the controller 304 calculate the window efficiency setting based on a number of factors including the thermal efficiency of the building. These factors can include, for example, the window efficiency settings of buildings that have similar characteristics, such as similar thermal efficiencies, similar building location, similar building age, similar building type, etc. In some examples, the controller 304 may use additional information regarding the windows in the building and/or information regarding the building itself to determine the window efficiency setting. In some cases, this additional information may be received from a user and/or may be accessed via a database. For example, the additional information regarding the windows may include, but is not limited to, the total number of windows in the building 200, the number of window panes in the windows, the manufacturer of the windows, the type of the windows, the model number of the windows, the R-value for the windows, a size of the largest window in the building, a size of the window in what is expected to be the coldest location in the building, and/or the age of the windows. In some cases, the additional information regarding the building may include, but is not limited to, the age of the building, the square footage of the building 200, the R-value of the walls of the building, the wall thickness of the building, and the age of the building. In some cases, the controller 304 may use information regarding the building 200, received from a public database, to determine the window efficiency setting. For example, the information from the public database may include, but is not limited to, the age of the building, the repairs performed to the building 200, the year and make/model of the HVAC equipment in or around the building, and the current and past occupants of the building. These are just a few examples of factors regarding the building 200 that may be used to determine the window efficiency setting. In some cases, more or alternative factors may be used to obtain a more accurate measure of the window efficiency setting.

In some cases, the controller 304 may the window efficiency setting and the received outdoor temperature to determine a humidity threshold for the building. The humidity threshold will be dependent on the window efficiency setting, the outdoor temperature, and to some degree the indoor temperature. In some cases, the controller 304 may use the network adapter 308 to communicate instructions for controlling the humidifier to the HVAC controller 301 so as to not raise the humidity in the building above the humidity threshold.

FIG. 4 shows an example method 400 for operating HVAC equipment of a building. Method 400 begins at step 402, where indoor temperatures and outdoor temperatures of the building are received. At step 404, a measure of thermal efficiency of the building is determined using the indoor temperature, the outdoor temperature, and control signals indicative of the thermal demand on a heater of the building. In some examples, control signals provided to the heater to control the indoor temperature of the building may be received and monitored and used to determine the thermal efficiency of the building. For example, a thermal demand on the HVAC equipment may be determined from the cycle ON time and the cycle OFF time of the heater. For example, the thermal demand on the HVAC equipment may be proportional or otherwise related to the cycle rate of the HVAC equipment 124 (e.g. the period of one ON/OFF cycle of the heater) when controlling to a particular set point temperature. In other cases, the thermal demand on the HVAC equipment may be determined from a modulated output signal that is provided to a modulating heater. For example, the thermal demand on the HVAC equipment may be proportional or otherwise related to the modulated output (e.g. 45% of Max) provided to the HVAC equipment. These are just examples.

In some cases, a temperature schedule may include a plurality of time periods, such as a comfort time period and a setback time period, each with a corresponding temperature setpoint. In some instances, the setback time period may be immediately after the comfort time period. A rate of change of the indoor temperature during a sensing period that begins after the heater is cycled OFF but before the heater is cycled back ON again (e.g. during a period when the heater remains OFF). In one example, the sensing period may begin at the end of the comfort time period and extend to before the indoor temperature reaches the lower setback temperature setpoint of the setback time period. This may provide a rate of thermal loss from the building when no heat is added by the heater. In some cases, the heater may be simply turned off for a sensing period of time, and over-ride a current temperature schedule if any. In any event, the thermal efficiency of the building may be determined using the indoor temperature, the outdoor temperature, and the rate of change of the indoor temperature.

Regardless of how the measure of thermal efficiency of the building is determined, the measure of thermal efficiency of the building may be used to determine a window efficiency setting as shown at step 406. In some cases, the thermal efficiency of the building is simply mapped to a corresponding window efficiency setting for the building (e.g. using look up table or the like). In other cases, window efficiency setting is calculated based on a number of factors including the thermal efficiency of the building. These factors can include, for example, the window efficiency settings of buildings that have similar characteristics, such as similar thermal efficiencies, similar building location, similar building age, similar building type, etc. In some examples, the controller 304 may use additional information regarding the windows in the building and/or information regarding the building itself to determine the window efficiency setting. In some cases, this additional information may be received from a user and/or may be accessed via a database. For example, the additional information regarding the windows may include, but is not limited to, the total number of windows in the building 200, the number of window panes in the windows, the manufacturer of the windows, the type of the windows, the model number of the windows, the R-value for the windows, a size of the largest window in the building, a size of the window in what is expected to be the coldest location in the building, and/or the age of the windows. In some cases, the additional information regarding the building may include, but is not limited to, the age of the building, the square footage of the building 200, the R-value of the walls of the building, the wall thickness of the building, and the age of the building. In some cases, additional information regarding the building 200, received from a public database, may be used to determine the window efficiency setting. For example, the information from the public database may include, but is not limited to, the age of the building, the repairs performed to the building 200, the year and make/model of the HVAC equipment in or around the building, and the current and past occupants of the building. These are just a few examples of factors regarding the building 200 that may be used to determine the window efficiency setting. In some cases, more or alternative factors may be used to obtain a more accurate measure of the window efficiency setting.

In some cases, the controller 304 may the window efficiency setting and the received outdoor temperature to determine a humidity threshold for the building, as shown at step 408. The humidity threshold will be dependent on the window efficiency setting, the outdoor temperature, and to some degree the indoor temperature. The HVAC equipment may then be controlled so as to not raise the humidity in the building above the humidity threshold, as shown at step 410.

Method examples described herein can be machine or computer-implemented at least in part. Some examples can include a computer-readable medium or machine-readable medium encoded with instructions operable to configure an electronic device to perform methods as described in the above examples. An implementation of such methods can include code, such as microcode, assembly language code, a higher-level language code, or the like. Such code can include computer readable instructions for performing various methods. The code may form portions of computer program products. Further, in an example, the code can be tangibly stored on one or more volatile, non-transitory, or non-volatile tangible computer-readable media, such as during execution or at other times. Examples of these tangible computer-readable media can include, but are not limited to, hard disks, removable magnetic or optical disks, magnetic cassettes, memory cards or sticks, random access memories (RAMs), read only memories (ROMs), and the like.

The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more aspects thereof) may be used in combination with each other. Also, in the above description, various features may be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the Description as examples or embodiments, with each claim standing on its own as a separate embodiment, and it is contemplated that such embodiments can be combined with each other in various combinations or permutations. 

What is claimed is:
 1. A controller for operating HVAC equipment of a building having one or more windows, the HVAC equipment including a heater and a humidifier, the controller is configured to: receive an indoor temperature within the building and an outdoor temperature outside of the building; determine a measure of thermal efficiency of the building based at least in part on the indoor temperature, the outdoor temperature and one or more control signals provided to the heater that are indicative of a thermal demand on the heater; determine a window efficiency setting based at least in part on the determined measure of thermal efficiency; determine a humidity threshold based at least in part on the window efficiency setting and the outdoor temperature; and control the humidifier of the building to not raise the humidity in the building above the humidity threshold.
 2. The controller of claim 1, wherein the measure of thermal efficiency of the building is determined while the heater is controlling the indoor temperature of the building in accordance with a constant temperature setpoint.
 3. The controller of claim 1, wherein the heater comprises a modulating furnace with a modulating heat output that is modulated by a control input, and wherein the one or more control signals include the control input.
 4. The controller of claim 3, wherein the control input to the modulating furnace is provided by a PI controller.
 5. The controller of claim 1, wherein the heater is cycled on and off by a heater relay output to control the indoor temperature of the building in accordance with a temperature setpoint, wherein the one or more control signals include the heater relay output.
 6. The controller of claim 5, wherein a cycle rate of the heater relay output is indicative of the thermal demand on the heater.
 7. The controller of claim 1, wherein the controller comprises a thermostat located within the building.
 8. The controller of claim 1, wherein at least part of the controller is implemented in a server remote from the building.
 9. A controller for operating HVAC equipment of a building having one or more windows, the HVAC equipment including a heater and a humidifier, the controller is configured to: receive an indoor temperature within the building and an outdoor temperature outside of the building; cycle the heater ON and OFF to control the indoor temperature of at least part of the building in accordance with a temperature schedule, wherein the temperature schedule includes a plurality of time periods each with a corresponding temperature setpoint, and wherein the temperature schedule includes a comfort time period with a comfort temperature setpoint followed by a setback time period immediately following the comfort time period with a lower setback temperature setpoint; determine a measure of thermal efficiency of the building based at least in part on the indoor temperature, the outdoor temperature and a rate of change of the indoor temperature during a sensing period extending from after the heater is cycled OFF at the end of the comfort time period to before the indoor temperature reaches the lower setback temperature setpoint of the immediately following setback time period; determine a window efficiency setting based at least in part on the determined measure of thermal efficiency; determine a humidity threshold based at least in part on the window efficiency setting and the outdoor temperature; and control the humidifier of the building to not raise the humidity in the building above the humidity threshold.
 10. The controller of claim 9, wherein the controller is configured to determine a measure of thermal efficiency of the building based at least in part on the indoor temperature, the outdoor temperature and the rate of change of the indoor temperature during a period after a user manually adjusts a current temperature setpoint downward to a lower temperature setpoint to before the indoor temperature reaches the lower temperature setpoint.
 11. The controller of claim 9, wherein the heater remains OFF during the sensing period.
 12. The controller of claim 9, wherein the controller comprises a thermostat located within the building.
 13. The controller of claim 9, wherein at least part of the controller is implemented in a server remote from the building.
 14. A controller for operating HVAC equipment of a building having one or more windows, the HVAC equipment including a heater and a humidifier, the controller is configured to: receive an indoor temperature within the building and an outdoor temperature outside of the building; determine a measure of thermal efficiency of the building based at least in part on the indoor temperature, the outdoor temperature and a sensed parameter that is related to a rate of heat loss of the building; receive information from a user regarding the one or more windows; determine a window efficiency setting based at least in part on the determined measure of thermal efficiency and the information received from the user regarding the one or more windows; determining a humidity threshold based at least in part on the window efficiency setting and the outdoor temperature; and controlling a humidifier of the building to not raise the humidity in the building above the humidity threshold.
 15. The controller of claim 14, wherein the information received from the user includes one or more of a total number of windows in the building, a number of window panes in the windows in the building, a manufacturer of the windows in the building, a type of the windows in the building, a model number of the windows in the building, and an age of the windows of the building.
 16. The controller of claim 14, further comprising receive information from the user regarding the building, and determine the window efficiency setting based at least in part on the determined measure of thermal efficiency, the information received from the user regarding the one or more windows and the information received from the user regarding the building.
 17. The controller of claim 16, wherein the information received from the user regarding the building includes one or more of a building square feet, a R-value of walls of the building, a wall thickness of the building, and an age of the building.
 18. The controller of claim 14, further comprising receive information from a public database regarding the building, and determine the window efficiency setting based at least in part on the determined measure of thermal efficiency, the information received from the user regarding the one or more windows and the information received from the public database regarding the building.
 19. The controller of claim 14, wherein the controller comprises a thermostat located within the building.
 20. The controller of claim 14, wherein at least part of the controller is implemented in a server remote from the building. 